The most typical solid polymer electrolytic fuel cell is configured by a polymer electrolyte membrane supported by a frame member having a gasket for sealing gas placed on its peripheral portion, an electrolyte membrane-electrode assembly (MEA) formed by an anode joined to one of the surfaces of the electrolyte membrane and a cathode joined to the other surface of the electrolyte membrane, and an anode-side conductive separator plate and a cathode-side conductive separator plate that sandwich the MEA, and a gas supply unit for supplying a fuel gas and an oxidizing agent gas to the anode and the cathode, respectively, is formed on a peripheral edge of the center portion in the separator plate, which is placed in contact with the MEA.
However, as shown in FIG. 12, since this conventional solid polymer electrolytic fuel cell has a gap 303 between the inner edge of a frame member 300 and an electrode 302, which is required upon assembling the frame member 300 and the separator 301, a phenomenon referred to as a cross-leak, in which a part of gas supplied into the fuel cell is discharged through this gap 303, tends to occur.
In order to prevent this phenomenon, as shown in FIG. 13, a structure has been proposed in which a second gasket 308 is placed in this gap 303 (Patent Document 1), and a method (Patent Document 2) has been proposed in which one portion of an inner edge of a gasket and an outer edge of an electrode 302 are disposed so as to be partially placed in contact with each other.
Moreover, the polymer electrolyte membrane is assembled virtually in the center of the thickness of the frame member, and with respect to its joining method, methods such as thermal compression bonding, bonding agent, and mechanical cramping, have been adopted.
Patent Document 1: Japanese Patent Application No. 2004-296702 (published as WO 2006/040994 A1)
Patent Document 2: Japanese Unexamined Patent Publication No. 2005-100970